--获取 请求参数：
local request_method = ngx.var.request_method
local args = nil
--1、获取参数的值 获取前端提交参数
if "GET" == request_method then
    args = ngx.req.get_uri_args()
elseif "POST" == request_method then
    ngx.req.read_body()
    args = ngx.req.get_post_args()
end
local operation = args["operation"]